How many base pairs are present in each full turn of the DNA double helix ?

Options

A. 4
B. 6
C. 8
D. 10

Answer

To determine how many base pairs are present in each full turn of the DNA double helix, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of DNA**:
- DNA is composed of two strands that coil around each other to form a double helix. Each strand is made up of nucleotides, which consist of a sugar, a phosphate group, and a nitrogenous base.

2. **Identify the Base Pairs**:
- The nitrogenous bases in DNA pair specifically: adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). These pairs are known as base pairs.

3. **Determine the Number of Base Pairs in a Full Turn**:
- In the DNA double helix, it is established that there are approximately 10 base pairs per complete turn of the helix. This is a characteristic feature of the DNA structure.

4. **Conclude the Answer**:
- Therefore, the number of base pairs present in each full turn of the DNA double helix is **10**.

### Final Answer:
The number of base pairs in each full turn of the DNA double helix is **10**.

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